OBJECTIVES: The aim of this study was to describe the development of an intervention to support the reproductive health of garment factory workers in Cambodia. DESIGN: A qualitative study informed by intervention mapping which included semistructured interviews and participant observation, followed by intervention development activities including specifying possible behaviour change, designing the intervention, and producing and refining intervention content. SETTING: The research was conducted by a multidisciplinary team with backgrounds in public health, linguistics, digital cultures and service delivery in a suburb of Phnom Penh where many garment factories cluster. PARTICIPANTS: Garment factory workers in Cambodia; typically young women aged under 30 years who have migrated from rural areas to Phnom Penh city. OUTCOMES: Analysis of reproductive health issues facing garment factory workers and metrics of videos developed. RESULTS: Our research identified some challenges that Cambodian garment factory workers experience regarding contraception and abortion. Concerns or experience of side-effects were identified as an important determinant leading to non-use of effective contraception and subsequent unintended pregnancy. Financial constraints and a desire to space pregnancies were the main reported reasons to seek an abortion. Information about medical abortion given to women by private providers was often verbal, with packaging and the drug information leaflet withheld. In order to address limitations in the provision of accessible reproductive health information for factory workers, and given their observed widespread use of social media, we decided to make three 'edutainment' videos about family planning. Key social media metrics of the videos were evaluated after 1 month. CONCLUSIONS: We describe the development of an intervention to support reproductive health among garment factory workers in Cambodia. These videos could be further improved and additional videos could be developed. More work is required to develop appropriate and effective interventions to support reproductive health of garment factory workers in Cambodia.